It was not exactly a surprise when, on July 10, 2006, Lech Kaczynski, president of Poland, appointed his twin brother, Jaroslaw Kaczynski, as prime minister. When the brothers’ Law and Justice (PiS) party won a plurality in the elections of Sept. 25, 2005, and formed a ruling coalition, many had expected that Jaroslaw would become prime minister. He declined the post amid speculation that he did not want to hinder his brother’s campaign for the presidency, which Lech won in a runoff on October 23. Less than a year later, however, Lech nominated Jaroslaw for the position and thus ensured that government power was firmly in their hands.

Identical twins, Jaroslaw and Lech Kaczynski were born on June 18, 1949, in Warsaw. Many older Poles remembered them as child actors who had appeared in the 1962 film Those Two Who Would Steal the Moon. The brothers were both educated at Warsaw University, and both later earned doctorates in law, Jaroslaw at Warsaw and Lech at Gdansk University. During the 1970s, as students, they were active in anticommunist movements, and Lech was jailed briefly (1981–82) by the government. Although both worked for a short time in education, by the early 1980s they had become active in Solidarity, the movement headed by Lech Walesa. Lech Kaczynski held leadership positions in the movement, and in 1989–90 Jaroslaw edited its newspaper. With the rise of Solidarity to power in 1989, both began active careers in government. They formed the Center Alliance in 1990, which Jaroslaw headed until 1998. Both brothers won election to the parliament, and they held a number of government appointments. By 1993, however, the pair had begun a falling out with Walesa, and in 2001 they formed PiS, headed (2001–03) by Lech and from 2003 by Jaroslaw. From 2002 to 2005 Lech served as mayor of Warsaw, while Jaroslaw continued in the parliament.

The Kaczynskis did not fit neatly into traditional political categories. They were nationalistic (even xenophobic) and aggressive in foreign policy, often hostile to the policies of the European Union, and sharply critical of the country’s historical enemies, Germany and Russia. They took a strong stand against the perennial problem of corruption in Poland. At the same time, there were populist elements in their views; although they advocated a strong central government, they also promoted both tax cuts and a strong economic safety net. On social issues they were deeply conservative, strictly following the doctrines of the Roman Catholic Church. The two differed in at least one important respect. Lech was the more outspoken, polarizing figure, capable of riling people with his blunt pronouncements, while Jaroslaw was considered more the calculating diplomat.

For more recent information on the subjects of this Britannica Year in Review biography, please see the articles on Jaroslaw Kaczynski and Lech Kaczynski.